Certain types of vacuum pump in both industrial and laboratory environments generate a considerable amount of noise thereby making working conditions in their vicinity less comfortable. Examples of pumps which are in particular need of noise reduction include roughing pumps, i.e. pumps employed to achieve a low vacuum, e.g. typically not less than 1×10−3 mbar. Roughing pumps are often used in combination with higher vacuum pumps, e.g. turbomolecular pumps. Many types of higher vacuum pumps do not work well at atmospheric pressure so that a roughing pump is needed to provide a low vacuum in which the higher vacuum pump can work to achieve the higher vacuum. Rotary pumps, e.g. rotary vane pumps, are commonly used roughing pumps in need of noise reduction. Other types of roughing pump in need of noise reduction include, without limitation, roots pumps, piston pumps, scroll pumps, membrane pumps and the like. Roughing pumps typically form a part of a vacuum pumping system for a mass spectrometer.
Noise reducing enclosures for roughing pumps currently on the market comprise a box in which the pump is completely enclosed. Such enclosures are available, for example, from Sonation GmbH (as described on their website at www.sonation.de) and MS Noise (as described on their website at www.msnoise.com). The enclosures are designed to enclose pumps in a laboratory setting, e.g. pumps of mass spectrometry systems. The pump noise is reduced but the box is necessarily bulky, complex and costly because sufficient ventilation must be provided with the box to prevent overheating of the pump. The ventilation is provided by fans, which require a power supply (thereby adding to the total power consumption) and maintenance and they are a source of noise themselves. The box must also be adapted in order to allow feed through of the necessary power, vacuum and exhaust lines to the pump inside. Moreover, full enclosure by the box makes the pump harder to reach which, in turn, makes maintenance of the pump more difficult.
In view of the above background, the present invention has been made.